The present invention relates to skis and more particularly to portable skis which may be folded or disassembled.
The presently used downhill (Alpine) ski is relatively long; for example, a typical downhill ski may be 5 to 61/2 feet in length.
It is inconvenient to travel with, or store, such long skis. Often they are too long to fit in the trunk of an automobile and they are awkward to carry onto a bus, subway or taxi. If one wishes to take one's skis to the office and leave on a ski trip after work, it is awkward to carry them to the office, store them during the day, and carry them on a trip.
These inconveniences have been recognized for many years, but a commercially acceptable portable ski, which folds or may be disassembled, is not yet available.
The ski is a highly engineered product. It must be relatively light in weight, so that it can be lifted and maneuvered on the snow without strain. Yet it must be strong and resilient to withstand constant shocks from turning, jumping and skiing over and between bumps.
Skiers are properly concerned with the "stiffness" of their skis, both in terms of axial torsion (twist about its imaginary axis) and longitudinal flexing (flexing perpendicular to its imaginary axis by pressure up or down at the ends of the ski).
It has proven very difficult to reconcile the competing objectives of a ski that will be foldable or disassembled, and yet which is desirable in its stiffness, resilience, weight and feel.
The advantages of a folding or disassembled ski have been known for many years and the patent literature shows many attempts to provide such a ski. For example, U.S. Pat. No. 3,689,093 entitled "Folding Ski" shows a ski having a mid-point hinge and end plates in which the ski is held together by a steel cable. In U.S. Pat. No. 3,884,315 entitled "Safety Ski" a ski has three hinged sections. The ski is a safety device, to prevent injury, and it does not fold for the convenience of folding and storage. U.S. Pat. No. 4,155,568 entitled "Sectional Ski" shows a ski which may be completely disassembled and has end plates having a coupling bar and notch. In U.S. Pat. No. 4,248,449 entitled "Cantilever Two Piece Ski" there is shown a cross-country ski which may be disassembled into two pieces. Each ski piece has a matching end plate and the ski pieces are joined by fasteners at their sides. U.S. Pat. No. 2,332,404 entitled "Hinged Ski" shows a two-piece ski which is hinged at its center and has studs and wing nuts to secure the ski in its assembled form. U.S. Pat. No. 3,439,928 entitled "Sectional Ski" shows a two-piece ski which is joined by male and female end connectors and a tightening screw. U.S. Pat. No. 3,730,544 entitled "Collapsible Ski Pole" shows ski poles which may be taken apart and reassembled.